Twin-governor mechanism for mixed-pressure turbines.



.0. JUNGGREN. TWIN GOVERNOR MECHANISM FOR MIXED PRESSURE TURBINESU APPLIOATION FILED NOV. 10, 1911.

1,089,709, Patented Mar. 10, 1914 2 BHBETS-SHBET 1.

WI tn ess e s: In r/en tor:

Osca/"Junggren,

His fTttorn qg.

0. J UN GGREN TWIN GOVERNOR MECHANISM FOR MIXED PRESSURE TURBINBS.

APPLICATION FILED NOV.10, 1911. 1,089,709.

Patented Mar. 10, 1914.

2 SHEBTS -SHEET Witnesses: Inventor. 1 W Osca/"Jun gran, W74 figs/M warning of the high pressure valves. The

NlTitli) STATES FATE NT Oil Flt) OSCAR JUNGGREN, 01E SCHENEGTADY, NEW YORK, ASSIGNOR T0 GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

TWIN-GOVERNOR MECHANISM FOR MIXED-PRESSURE TURBINES.

'10 all whom it may concern:

lie it known that I, ()scan Junoounn, a eitizen of the United States, residing at fie]reneetiuiy, county of Schenectady, State of New York, have invented certain new and useful improvements in Twin-Govern0r Mechanism for hllXGd-PPQSSUI'O Turbines, of which the following is a specification.

The present application is a continuation of my application, Serial No. 641,015, filed July 28th, 1911. I

This invention relates to what are known as mixed pressure turbines, or in other words, elastic l'luid turbines driven normally by steam or other elastic fluid at a low pressure, but provided with means for admitting steam UPOtllOl elastic fluid at high pressure 'lu. never it. becomes necessary to su 'iplemrnt the supply of low pressure fluid in order to carry an increased load, or to compensate for a drop in the supply of low pressure fluid. The high pressure is thus held in reserve, as it were, to be used in case of necessity, and the customary arrangement is to govern such a machine by means of one speed govt-truer, in which half of its stroke is assigned to the low pressure valve mechanism of the machine and the other half to the high pressure valves. The same result can be :urcomplished by using two speed governors, bothigeared to the turbine shaft, one governor controlling the low pressure admission and the other the high pressure admission. The governors are so constructed that they operate in succession, the one controlling the low pressure steam and turning the admission valve almost wide open before the other governor begins to open the high pressure admission valves. The closing of the valves takes place in the reierse order. This arrangement is practit-ally the sann as when one governor alone is utilized to control both steam pressures, but it has a distinct advantage in that by means ot a rompm'isating device the high pressure valve: am be brought into operation out of their usual time, if necessary, and iiulemndently oi? their own governor. Thisv run he done either without interfering with the operatiol'l oi the low pressure governor. or on the other hand the compensating device can be caused to close the low u'essure valve simultaneously with the Specification of Letters Patent.

Continuation of application Serial No. 641,015, filed July 28, 1911.

Serial No. 659,474.

Patented M ar. 10, 1914.

This application filed November 10,

object of this arrangement is to compensate tor a drop or lnterruption of the supply of low pressure steam in the case of a mixed pressure turbine driving an alternating current generator coupled in parallel with other alternators driven by other prime movers and independently governed and which are not subject to variations in steam pressure. Under such conditions, the mixed pressure unit will run at the same speed as the others even when there is a deficiency of low pressure steam. Governors responsive to speed variations only will therefore be inadequate to effect the valve changes required to supplement this deficiency by a supply of high pressure steam. I therefore provide the compensating device above referred to, comprising a movable abutment, such as a flexible diaphragm, exposed on one side to the tluid pressure in the low pressure conduit, and on the other side to atmospheric pressure, and biased against the atllltlsplltlic pressure by a spring or its equivalent. The diaphra m is connected, through a lost motion device, with the high pressure governor, so that when .he pressure in the low pressure conduit becomes red ueed below the value necessary for earrying the load, the diaphragm will be tlexed by the air pressure against the spring and that of the pressure of the low pressure source and will cause the governor to open 'its valves and admit high pressure steam,

independent of the speed of the machine. By this device, the mixed pressure unit will carry approximately the sat l0 load, whether it has the full amount of low pressure steam supplied to it, or only a reduced quantity supplemented byhigh pressure steam, and in either case at normal speed.

In many installations it is desirable never to permit the pressure in'the low pressure conduitto fall below that of the atmos phere, because in that case air will be sucked into the system and break down the vacuum in the condenser. This can be prevented by connecting the diaphragm oi. my eompensating device not only with the high pressure governor but also with the low pressure governor, so that as soon as the high pressure valve or valves is or are opened the low pressure valve will be closed and will remain so until the pressure in the low iressure conduit is restored to atmospheric 1' above.

The accompanying drawings are end elerations, partly in section, of a miXed pressure turbine equipped with twin speedgovernors and my compensating device, Figure 6 1 showing it applied to the high pressure governor only, and Fig. 2 showing the arrangeme'nt for closing the low pressure "alve when the high pressure valve is opened by said compensating device.

The turbine has a casing 1 supported on. a base 2. It is supplied with low pressure steam through a conduit 3 and with high pressure steam through a main 4, controlled respectively by the butterfly valves 5, 6. The spindles of these valves are respectively connected to the operating motors, and as these motors are identical in construction, a description of one will sufiice for both.

The valve spindle is connected with a rod 7 attachedto a movable abutment, preferably a piston 8 working in a cylinder 9. A pilot valve 10. in a valve chest 11 controls ports leading to the ends of said cylinder. Fluid under pressure is conveyed 'to the valve chest by a pipe 12, the exhaust being led off by the pipe 13. The stem 14 ofthe pilot valve is pivoted to a floating lever 15, one end of which is pivotally connected to a follow-up lever 16, fulcrumed on the valve chest and pivoted to the rod 7. 'The other end of the floating lever is connected by a link 17 with the transmission lever 18 of the governor. Upon a decrease of speed, the governor weights fall and the transmission lever is moved upward, raising the pilot valve and admitting fluid ressure above the piston to open the butterfly valve more or less and decrease the supply of steam to the turbine. If the speed runs up above normal, the butterfly valve is correspondingly closed to reduce the flow of steam.

I provide two speed governors, one of them 19 controlling the motor which operates the low pressure butterfly valve 5, and the other one 20 controlling the high pressure valve 6. Both governors are geared to the turbine shaft 21, but their weights and spring tension are so adjusted that they operate in succession, as explained above.

flexible metallic diaphragm 22 inclosed in a casing 23 which is connected by a pipe 24 with the low pressure conduit 3 in advance of the valve 5. A stop valve 25 controls the pipe .4. Acting in conjunction with the pressure of the steam against the diaphragm is a spring 26, whose tension can be adjusted by a screw 27 tapped through the top of the casing. Thisspring is soadjusted that the diaphragm will not move upwardly until the steam pressure in the conduit 3 drops to atmospheric or thereabout. A rod 28 is attached to the diaphragm and passes through a bearing 29 in a bridge piece below the cas- 6 ing. It will thus be seen that the under side My compensating device consists of aof the diaphragm is exposed to atmospheric pressure. A lever 30 is fulcrumed to a stud 31 on said bridge piece, and is pivoted to said rod. A link 32 connects said lever with the transmission or governor actuated lever of the high pressure governor by a lost motion device, such as a pin and slot, as shown, so that the governor is free to act under'normal conditions, that is, so long as the supply of low pressure steam is main- 7 tained. But in case the pressure in the conduit 3 drops to that of the atmosphere, the pressure on the diaphragm 22 is lessened suflieiently to permit the air pressure acting on its under side to force up the rod 28 and raise the levers 30 and 18 and operate the pilot valve of the high pressure valve motor to admit fluid pressure above the piston of said motor and cause the opening of the valve 6 'to a greater'or less extent, so as to admit sufficient high pressure steam to compensate for the drop in the low pressure conduit. This action of the compensating device is of course supplemental to that of the high pressure governor, and is effective only when the speed of the machine persists V in spite of the drop in" low pressure steam, owing to the effect of the electrical connection between the alternator driven by this turbine and those driven by other engines;

From the foregoing it will be seen that the turbine under heavy load conditions will use all the steam from the low pressure source and also a greater or less amount of a steam from the high pressure source. So loo long as the low pressure source does not decrease in pressure below a 0811.. predeter mined amount the diaphragm mechanism will remain inactive but it is always on guard to modify the action of the high pressure speed governor whenever the steam supply conditions become abnormal.

Fig. 2 shows the arrangement for closing the low pressure conduit when the pressure falls to atmospheric, in order to prevent air from being sucked into the system. The lever 30 is replaced by a double-armed lever 33, one end of which is connected with ,the high pressure governor, as before. The

other end of said lever is connected by a 1115 link 34 and a lost motion device with the transmission lever o-fthe low pressure governor. hen the air pressure forces the diaphragm upward against the spring 26 it raises the rod 28 and actuates the lever 33 to open the valve 6, the downward movement of the link 34: occurring at the same time causes the low pressure valve-motor to close the valve 5 and thus prevent air from leaking into the turbine.

If the failure of the low pressure source is only partial, the valve 5 will partially close thereby maintaining a pressure in the conduit 3 thatis sufficiently high to prevent air leaks' in :urcordalute with the provisions of the patent; statutes, l. have described the principle of my invention, together with the apparatus which I: now consider to represent the best cmbmliment thereof; but'l desire to have it understood that the apparatus shown is only illustrative and that the invention can be carried out by other means.

What 1' claim as new and desire to secure by Letters .latent of the United States is:-

1. The combination with a mixed pressure turbine, ol twin speed governors, controlling respectively the low pressure conduit and the high pressure main, and a. compensating device responsive to a drop in pressure in the low pressure conduit and operating to open the high pressure main independently of its governor.

2. The comliiinz'ition with a mixed pressure turl'iine, of twin speed governors, controlling respectively the low pressure conduit and the high pressure main, a diaphragm exposed to the pressure in the low pressure conduit, and operative connections between said diaphragm and the high pressure governor.

The combination with a mixed pressure turbine, of twin speed governors mntrolling respectively the low pressure conduit and the high pressure main, a diaphragm exposed to the. pressure in the low pressure conduit, and connections between said diaphragm and the transmission lever of the high pressure governor, said connections including a lost motion device.

4-. The combination with a mixedv In'cssure turbine, of twin speed governors controlling respectively the low pressure conduit and the high pressure main, i'neans responsive to :1 drop in the low pressure fluid, and operative connections whereby said means can close the low pressure conduit and admit high pressuresteam irulc 'iendently of said governors.

The cmubination with a mixed pressure turbine, ol? twin. speed governors controlling respectively the low pressure conduit and the high pressure main, a dia ')hragm exposed to the low pressure fluid, a spring acting on said diaphragn'i, a lever connected with the diaphragm, and lost motion connections between said lever and the translnissioi'i lever ol the high pressure governor.

(3. The combination with a mixed pressure turbine, of twin speed governors controlling respectively the low pressure conduit and the high pressure main, a diaphragm exposed to the low pressure fluid, a spring acting on said diaphragm, a lever connected Willi said diaphragm, and lost i'notion connections be tween said lever and the transmission levers of both of said goveri'iors.

T. The combination with a mixed pressure turbine, ot' a low pressure supply conduit and a high pressure supply main therefor, a butterfly valve in each of said supply pipes, a lluid-press|u-e o ierating-motor for each of said valves, twin speed governors respectively controlling said motors -u lever having lost motion connections with the transmission levers of both governors, a diaphragm exposed to the fluid pressure in said low pressure supply conduit, and connections between said diaphragm and said lever.

B. In combination, a mixed pressure turbiue, a conduit admitting low pressure fluid thereto, a. conduit admitting high pressure lluid thereto, low and high pressure valves controlling the passage of fluid through the conduits, twin governors both responsive to speed changes of the turbine for controlling said valves, and a means responsive to pressure for modifying the action of one of the speed governors on the 'alve controlled thereby.

S). In combination, a mixed pressure turbine, a conduit admitting low pressure fluid thereto, a conduit admitting high pressure lluid thereto. low and high pressure valves controlling the passage of fluid through the conduits, a motor for actuating each of the valves, twin governors responsive to speed changes ol' the turbine for controlling the action of said motors, and a pressure responsive means for modifying the action of one ot the speed governors on the motor controlled thereby.

10. In ':ombination. a mixed pressure turbine. a. conduit admitting low n'essuro fluid thereto, a conduit admitting high pressure fluid thereto, low and high pressure valves cont-rolling the passage of fluid through the conduits, twin governors both responsive to speed changes oil the turbine for controlling said valves, and a pressure responsive means that is common to and modifies the action of both governors on said valves.

1.1. In combination, a mixed pressure turbine, conduits admitting low and high pressure fluid thereto, low and high pressure valves in said conduits, a pair of speed governors that are driven by and are responsive to changes in speed of the turbine for controlling said valves, the governors being so adjusted that the one controlling the low pressure valve opens it fully before the other governor opens the high pressure valve, and closes them in the reverse order, and a means responsive to"variations in pressure of the low pressure source for modifying the action of a governor on the valve controlled thereby.

12. In combination, a mixed pressure turbine, conduits admitting low and high pressure lluid thereto, low and high pressure valve means for controlling the passage of fluid through the conduits, twin governors for the valves, and a pressure responsive means which causes the low pressure valve Correction in Letters Patent No. 1,089,709.

' for the valves, and pressure responsive means which When the low pressure source of supply 1s deficient modifies the actlon of I of the case in the Patent Office.

[SEAL] the high pressure speed governor on its valve means and. assumes control of the low pressure valve means to the exclusion of its speed governor and causes the same to re strict the opening to the turbine.

' In Witness whereof, I have hereunto set my hand this 8th day of November, 1911.

OSCAR JUNGGREN.

Witnesses:

BENJAMIN B. HULL, HELEN Onrom).

y it is hereby certified that in Letters Patent No. 1,089,709, granted March 10, 1914:, upon the application of Oscar Jungg ren, of Schenectady, New York, for an improvement in Twin-Governor Mechanism for Mixed-Pressure, Turbines, an error appears in the printed specification requiring correction as follows: Page 2, line 38, for the word decrease read increase; and that the said Letters Patent should be read with this correction'therein that the same may conform to the record Signed and sealed this 31st day of March, A. 1)., 1914.

J. r. NEWTON,

Acting Commissioner of Patents. 

